“We find the story and the allegations very troubling. Mark Halperin is leaving his role as a contributor until the questions around his past conduct are fully understood,” said an MSNBC spokesman.

HBO Thursday also pulled the plug on a 2016 election project based on a yet-to-be-published book co-authored by Halperin. "HBO is no longer proceeding with the project tied to the untitled book co-authored by Mark Halperin and John Heilemann on the 2016 Presidential election," the network said in a statement. "HBO has no tolerance for sexual harassment within the company or its productions."

Showtime is also weighing its options on whether to bring back its politcal documentary series The Circus, which Halperin has co-hosted for two seasons. "During Mark’s time working with us, we have not seen nor have there been allegations of any untoward behavior," said Showtime in a statement. "We are aware of these reports and will continue to evaluate all options should we decide to move forward with another season of The Circus. There is no tolerance for sexual harassment within Showtime and its productions.”